Logout redirect to server root - no change possible

Hello,
I have some trouble with the joomshopping Login module. After fixing the problem with redirection to home after login regarding the forum topic I already have a LOGOUT problem - after logout the system redirect to server root directory but my page is located within a subdirectory (Error: Forbidden You don't have permission to access / on this server.). No effect if i change the redirect path within the login module. No such behavior if i use the Joomla login module.

// Check if the log out succeeded.
if (!($error instanceof Exception))
{
// Get the return url from the request and validate that it is internal.
$return = $input->$method->get('return', '', 'BASE64');
$return = base64_decode($return);